It's dark. Sunrise is still more than an hour away as Janet Evans tucks a last strand of dark hair beneath her latex swim cap.

"This is the hardest part," she says as she stares into the blue light reflected up out of the pool and prepares to plunge into another day of exhausting training. By day's end, Evans will have logged up to 10 miles in the pool and 45 minutes of intense training in the weight room.

Her goal seems an impossible dream, an Olympic comeback after 15 years in retirement. She will compete in U.S. Olympic Trials in the 800-meter freestyle next week.

As her slender body knifes through the water, it is easy to imagine that the clock has rolled back to 1988, when Evans burst onto the Olympic scene at 17 with three gold medal victories at Seoul, South Korea. Four years later, Evans added silver and another gold at the games in Barcelona. In 1996, she was a part of one of the most electrifying moments in Olympic history, when she passed the Olympic flame to Muhammad Ali in Atlanta's Opening Ceremonies.

Janet Evans won the 800-meter freestyle at the 1988 Seoul Olympics.

But by the '96 Olympics, Evans was burned out from over a decade of competition. "I was 24," she says, "I'd started to have a few shoulder problems. ... I was tired, you know?"

At 40, Evans still retains the effervescent smile that warmed the nation's heart so long ago. Gone is the pixie haircut. It's been replaced with a more sophisticated shoulder-length style more fitting a busy post-retirement career as a wife, a mother of two, an Olympics booster and a motivational speaker. She is currently representing Metamucil.

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Evans says those experiences, especially motherhood, have given her a more grounded perspective than she ever had at 17.

It was two years ago that Evans started thinking about a comeback. She was attending a swim meet and realized that the winning times hadn't really improved much in the 15 years since her retirement.

"Can I do this?" she texted her former coach, Mark Schubert.

"You'll never know unless you try," was his response. But Schubert warned that the distance races that were Evans' specialty can take a toll on a 40-year-old body.

Evans says she was back in the water the next day, the start of a two-year odyssey.

She swims six days a week now with members of the Golden West Swim Club, a team made up of kids less than half her age. "Those teenagers are an important part of my life," says Evans, "They motivate me."

But will that motivation be enough to return Evans to the top of her sport? Schubert says it just might.

Janet Evans, who carried the torch at the 1996 Olympics, hopes to swim at the London Games

"Her attitude is exactly the same as it was when she was younger," Schubert said. "I think Janet is going to amaze everyone with how fast she can swim."

Since announcing her comeback, Evans has heard from both supporters and critics.

" 'You've had your time.' I've heard that a lot," says Evans. "For me, it's a question of confidence and knowing that my legacy will be intact. (It's) being proud of the fact that at 40, I can come back and actually swim with 17-year-olds and keep up."